1. Field of the Invention
The present invention relates to a data input/output technology, and more particularly, to a technology for encrypting data to be secured and inputting/outputting the same between a storage device and a host device.
2. Description of the Related Art
With recent dramatic advances in size reduction, finer design rules, and larger-scale production of storage cells, storage media are being reduced in size and price, and increased in capacity. In these circumstances, the inventors have made attempts to implement a further improved recording medium of yet higher convenience, and to improve the use of a large-capacity hard disk which was conventionally used by fixedly connecting to a single host device. These attempts lead to a hard disk being configured to be detachable from the host device and thereby serve as a removable medium which allows the data to be shared among a plurality of host devices. The size-reduced, large-capacity hard disk that is accessible at relatively high speeds can be used as a removable medium with considerable merit.
For example, see Japanese Patent Laid-Open Publication No. 2000-173158 (its entirety incorporated herein by reference).
In view of user convenience, any host devices are desirably adapted to read or write data on the removable hard disk. On the other hand, this also means that the data may be possibly leaked to a third party.
Now that attention is focused on the distribution of digital contents such as music and pictures, it is critical to develop such a technology that can properly protect data to be secured technology in order to protect copyrights and prevent digital contents from being leaked out.